The invention relates to a cooling assembly for a wall box for a large-scale combustion device. The wall box is located within a wall port of the combustion device in order to receive a device, such as a cleaning device or an imaging device.
During the operation of large-scale combustion devices, such as boilers that burn fossil fuels, slag and ash encrustations develop on interior surfaces of the boiler. The presence of these deposits degrades the thermal efficiency of the boiler. Therefore, it is periodically necessary to remove such encrustations. Various systems are currently used to remove these encrustations.
One such type of system includes a device referred to as a “sootblower”. Sootblowers are used to project a stream of cleaning fluid, such as air, steam or water, into the interior volume of the boiler. In the case of long retracting type sootblowers, a lance tube is periodically advanced into and withdrawn from the boiler. As the lance tube is advanced into and withdrawn from the boiler, it rotates or oscillates in order to direct one or more jets of cleaning fluid at desired surfaces within the boiler. In the case of stationary sootblowers, the lance tube is always maintained within the boiler. Sootblower lance tubes project through openings in the boiler wall, referred to as wall ports. The wall ports may include a mounting assembly, such as a wall box, in order to properly position the lance tube with respect to the boiler wall.
Another such type of system includes a device commonly referred to as a “water cannon”. Water cannons involve the use of a monitor or nozzle positioned within a wall port in order to eject a stream of fluid, such as water, into the interior volume of the combustion device. The water cannon nozzle typically includes a pivot joint to permit adjustment of the direction of the stream of fluid. Similarly to the sootblower, the water cannon nozzle is positioned within the wall port via a mounting assembly, such as a wall box. Unlike the sootblower, however, the water cannon nozzle preferably includes a pivotable ball joint coupled with the wall box in order to adjust the direction of the stream of fluid flowing into the boiler interior volume. Due to the presence of the pivotable ball joint, the wall port for a water cannon assembly is typically larger than the wall port for a sootblower.
Other devices, besides cleaning devices, may penetrate the boiler wall via a wall port in order to perform a desired function. One such device is an imaging device, such as an infrared imaging device. Imaging devices are often used to examine the interior volume and the interior surfaces of the boiler in order to check the boiler status or to perform maintenance on the boiler. Similarly to the cleaning devices, the imaging device typically penetrates a wall port in order to view the boiler interior volume. The imaging device may be extended into the boiler interior volume similarly to a sootblower lance, it may be coupled with a pivoting ball joint similarly to a water cannon assembly, or it may be used in any other appropriate configuration. Regardless of the configuration of the imaging device, it typically includes a mounting assembly located within the boiler wall port.
During operation of the boiler, the boiler interior volume reaches extremely high temperatures. The boiler external walls include a plurality of tubes containing a fluid, such as steam or water, that flows through the tubes and undergoes heat exchange with the boiler interior volume gases. The heated fluid may then be used for various purposes, such as a heating medium. The tubes, hereinafter referred to as steam tubes, are typically placed side-by-side with each other in order to form a substantially continuous heat-transferring medium. However, the steam tubes must be diverted or discontinued in the area near the wall port in order to permit the penetrating device, such as the sootblower lance tube, the water cannon nozzle, or the imaging device, to penetrate the wall of the boiler. As a result, the area adjacent to the wall port is more directly exposed to the heated boiler gases than other areas of the boiler wall.
Currently, the area adjacent to the wall port is at least partially protected from the heated boiler gases by various methods. One such method is to provide a heat transfer plate that conducts heat from the boiler interior volume into the steam tube. More specifically, heat shields may be located adjacent to the wall port and connected to the steam tubes in order to conduct heat from the boiler gases into the steam tubes and prevent such heat from damaging or penetrating the wall box. Similarly, a crotch plate may be located adjacent to the wall port and connected to the steam tubes in order to conduct heat from the boiler gases into the steam tubes. Another such method of protecting the wall box is to provide a layer of refractory material adjacent to the wall port in order to absorb and/or resist the boiler gas heat.
One problem with the currently-used methods of protecting the wall box is that the refractory material, the heat shields, and crotch plate may undergo part wear over time, thus lessening the respective components' effective heat-reducing capabilities. Part wear may be further hastened by the high temperatures within the boiler interior volume. Another problem with the currently-used methods is that the refractory material, the heat shields, and crotch plate, even when fully intact, may not provide enough heat-reducing properties to sufficiently protect the wall box.
As seen from above, it is desirous to provide an improved system for protecting and cooling a wall box in order to improve the performance of the wall box, in order to improve the performance of the device coupled with the wall box, and in order to prevent premature component damage of both the wall box and the device.